1. Field of the Invention
The present invention relates to automated storage and retrieval systems (AS/RS), and more particularly to material handling systems for storing and accessing palletized material in large multi-story automated warehouse buildings.
2. Description of Related Art
Automated warehouses and automated storage and retrieval systems (AS/RS) can reduce costs, pilferage, and damage because far fewer workers are needed for otherwise similar operations.
Retrotech Incorporated (Fishers, N.Y.) markets various automated warehouse systems and material handling robots. One such system, ACTIV(trademark) is a mechanized material handling automation technology for continuous product flow. Loads are not assigned a location within a system, rather they are assigned a dynamic path into and subsequently through the system using a transport design that overcomes the limitations of conventional deep lane storage. The technology was originally marketed in Europe under the tradename ACTIV(trademark) by Naaraharju Oy in Finland. Typical applications for ACTIV(trademark) include existing warehouses which had their manufacturing sources nearby, and the packaging and palletizing lanes, loading docks, and other services were already in place.
But, the Retrotech system and other conventional approaches bog down and become very inefficient as the design capacity is reached. Users cannot immediately access every and any pallet of product without having to xe2x80x9cdig throughxe2x80x9d others to get to it. Systems like the Retrotech system have carts xe2x80x9cslaved togetherxe2x80x9d in groups that are constantly moving. Only one in the group is doing any useful work at any one time. U.S. Pat. No. 4,732,524, issued Mar. 22, 1988 to Seppo Suominen, describes some of the details found in the Retrotech systems. One of the disadvantages of this system include that the carts"" winch cables stretch and their drums wear out, and this affects the carts"" ability to stop at the proper location. Another disadvantage is that this system requires a high degree of maintenance.
It is also advantageous for any AS/RS system to be able to handle a wide variety of pallets. Some conventional systems are very particular about the pallets that can be used. If ordinary and inexpensive pallets could be utilized, the potential savings in pallet costs can amount to over $200,000 per year in a 10,000 pallet system.
In the Retrotech system, a pallet can be moved ten to thirty times before it is finally shipped out. Such excessive handling can cause unnecessary damage to the product, and may shift the load on the pallet making it unstable.
An object of the present invention is to provide an automated storage and retrieval system that is economical to install and operate.
Another object of the present invention is to provide an automated storage and retrieval system that is efficient and has high throughput.
Another object of the present invention is to provide a system that uses minimal labor.
A further object of the present invention is to provide an automated storage and retrieval system that handles the pallets and their loads as little as possible between input and output.
A still further object of the present invention is to provide a system that can operate at 100% capacity with no loss in efficiency.
Briefly, an automated warehouse system embodiment of the present invention is contained within a warehouse building with at least one freight elevator. One such freight elevator and shaft automatically accepts incoming material on pallets. A rotating forklift-like attachment mounted inside the loading elevator can extend its forks to reach out and bring in material loaded on a standard pallet from a delivery system. Once inside the loading elevator, the rotating forklift is spun around to face inside openings on the various floors of the warehouse system. When the elevator arrives at a designated level, the rotating forklift extends out and deposits the material and pallet on a temporary support just outside the elevator. Each floor has a rail trolley that shuttles along an aisleway between temporary supports for both the loading elevator and an unloading elevator, which in some embodiments may be the same elevator. When both a loading and an unloading elevator are used, these elevators are at opposite ends of the aisleway. Each aisleway is intersected by several row rails that are perpendicular to the aisleway. The rail trolley or aisle cart carries a battery powered row cart on top of it that can run back and forth along the row rails. The aisle cart is positioned at a designated row along the aisleway, and the piggyback carrier or row cart then moves off the aisle cart down the designated row for the purpose of carrying, depositing, and picking up material on pallets. Storage position slots are provided along each row, front to rear.
An advantage of the present invention is that a system is provided that gives immediate access to any set of pallets. A set of pallets is defined as the total pallets in any particular row.
Another advantage of the present invention is that an AS/RS system is provided that permits high density storage. Each module can have multiple levels with minimal clearance between the levels. Most of the space in the module is used for storage with the only open space being the aisleways.
A further advantage of the present invention is that an AS/RS system is provided that permits fast storage and retrieval, e.g., up to six pallet movements per minute per module based on a six level system. This greatly increases the throughput of the system.
An advantage of the present invention is that a system is provided that has quick response times to movement orders. Since all pallets are highly accessible, a pallet can be retrieved and delivered to the docks in a short period of time.
A further advantage of the present invention is that an AS/RS system is provided that is completely controlled by computer software that is in charge of all functions of the system, and therefore can be easily customized to fit the needs of even unique applications. Such software also allows for complete accounting and status of the stored inventory, and this helps control costs and increase profitability.
A still further advantage of the present invention is that an AS/RS system is provided that uses simple reliable components to help keep maintenance costs down, requiring less personnel to perform maintenance duties. This captive system allows for complete control of inventory preventing damage, early shipment of unreleased product, mis-shipments and pilferage. Complete accounting and status of inventory helps control costs and increases profitability. No constant rearranging of the pallets for optimization is required and the system by its nature is always optimized.